CLINICAL TOPICS

Spring Plants Toxic to Pets

Susan E. Yohn, DVM, MS, DABVP-Canine/Feline, DACVIM

The spring gardening season is just around the corner! Spring bulbs are ready to break through the ground, and we are ready to see renewed greenery. Dogs and cats are natural diggers and chewers and may ingest leaves, bulbs or flowers from common garden plants. Fortunately, while there are many species of garden plants, only a small percentage are truly poisonous to pets. While the majority of plant toxins result in gastrointestinal signs, a few plant toxins can be life threatening. It is important for the veterinary team to be aware of the most common garden plants that can be toxic to pets. The goal of this article is to review some common spring plants that may be of risk to dogs and cats, including discussion of the toxin involved, clinical signs and therapy if ingestion is suspected.

Tulips and Hyacinths

These spring flowering bulbs contain allergenic lactones called tuliposide A and B. Tuliposides are in all parts of the plants but most concentrated in the bulbs, which also contain calcium oxalate crystals. The greatest danger is to dogs that tend to dig up and chew the bulbs. Clinical signs include hypersalivation, vomiting, diarrhea and depression. With large amounts of bulb material ingested, tachycardia and dyspnea can be seen. There is no antidote, and therapy is supportive including rinsing out the mouth, fluid therapy, antiemetics and GI protectants. Blood pressure and ECG monitoring, anticonvulsants or antiarrythmics may be necessary in severe cases.

Daffodils (Narcissus)

These flowers contain lycorine, an alkaloid with emetic properties. Ingestion of the bulb, plant or flower can cause clinical signs including vomiting, diarrhea, abdominal pain, cardiac arrhythmias, hypotension, respiratory depression and possibly CNS signs (tremors, seizures). Severity of the clinical signs are related to the amount of plant material ingested. As with tulips and hyacinths, there is no antidote, and supportive care is similar to that for tulip or hyacinth ingestion based on the clinical signs of the pet at presentation.

Foxglove and Lily of the Valley

These are two of several garden plants that contain cardiotoxic cardenolides or bufaliendolides. These are naturally occurring cardiac glycosides related to digoxin.

All parts of the plants are toxic; even water from a vase that holds flowers from these plants can be toxic. The toxins block the function of the cellular ATP Na-K pump which causes increased intracellular sodium and decreased intracellular potassium. Cardiovascular signs (brady or tachyarrhythmias, AV block, asystole), hyperkalemia, gastrointestinal signs (hypersalivation, vomiting), or central nervous system signs (mydriasis, tremors, seizures) may be seen. Diagnostics for a pet suspected of ingesting these plants should include renal and electrolyte status, ECG and blood pressure. Therapy includes fluids and colloid support for blood pressure, antiemetics, antiarrythmics and anticonvulsants. The antidote, digoxin-specific Fab fragments, is available on the human market but is cost prohibitive.

Azaleas and Rhododendrons

These common shrubs contain grayanotoxins that bind to sodium ion channels in cell membranes of cardiac and skeletal muscle cells. Sodium transport is blocked and the cell remains depolarized. All parts of the plant are considered poisonous.

Although fatal toxicosis is rare in humans, ingestion of only small amounts of leaves in dogs or cats can cause severe symptoms including coma or possible death.Symptoms occur after a latent period of minutes to three hours and include hypersalivation, vomiting, weakness and paresthesia in the extremities. With large amounts of plant ingestion, symptoms can include loss of coordination, progressive muscular weakness, bundle branch block and/or ST-segment elevations, hypotension and profound bradycardia. Fluid and colloid support, antiemetics, atropine therapy, vasopressors and other agents are used to manage clinical symptoms.

Lilies (Lilium) and Daylilies (Hemerocallis)

There are toxic and benign lilies found in the garden or in floral arrangements in the home. Calla and Peace lilies contain insoluble oxalate crystals that can cause minor signs of tissue irritation to the mouth, tongue, pharynx and esophagus. Drooling is usually the presenting clinical sign, and no extensive medical management is necessary.

The “true” toxic lilies include Tiger, Asiatic, Easter, Japanese Show, and Day lilies. The toxin in lilies has not been identified, but all parts of the plant including the pollen and water in a vase that has held the flowers or foliage are toxic to cats. Dogs and humans are not susceptible to this toxin, but even small ingestion of leaves or petals can result in severe kidney failure in cats. Clinical signs are seen within hours of ingestion and include vomiting, depression and anorexia. Acute renal failure can progress to anuric renal failure in 1 to 3 days. Lab profiling shows severe azotemia, with epithelial casts on urinalysis, proteinuria and glucosuria. Treatment includes decontamination (induce vomiting, activated charcoal), antiemetics, gastroprotectants and IV fluid diuresis. Peritoneal or hemodialysis is appropriate for cats with anuric renal failure. Early and aggressive decontamination and fluid therapy is important in successful management. Subcutaneous fluids are not adequate for therapy in lily toxicosis. If supportive care is initiated after 18 hours of ingestion or if anuria develops, prognosis is poor.

Spring Houseplants

There are some common plants brought into the home as spring approaches and associated with the holidays. A few of these plants need to be considered toxic. The Shamrock plant, sold around St. Patrick’s Day, contains soluble calcium oxalates which can cause gastrointestinal signs. The oxalates can be absorbed and bind to systemic calcium resulting in hypocalcemia and deposition of calcium oxalate crystals in the kidneys.

Kalanchoe plant

The likelihood of this toxicity is low, but dehydrated pets or those with renal insufficiency may be more at risk. Therapy is rehydration and diuresis. Easter lilies, which have already been discussed, are commonly brought into the home during the Easter holiday season and should be avoided in homes with cats. Kalanchoe plants, sold as flowering houseplants in the spring, contain cardiac glycosides like their cousin, foxglove. All of the plant is considered toxic with clinical signs and treatment the same as discussed for foxglove. This is another house plant that should be avoided in homes with dogs and cats.

This is not an exhaustive list of toxic spring plants. When possible toxic plant ingestion is suspected, supportive care should be considered while information is obtained to verify the exact plant species consumed. Local horticulturists or florists may serve as good resources to verify plant identification. While the majority of plant toxins result in gastrointestinal signs, a few plants toxins can be life threatening. Whenever toxic plant ingestion is suspected, Animal Poison Control (ASPCA) should be consulted (888.426.4435) to more specifically direct medical management to ensure a good outcome for the pet.

Critical Care: When Should A Case Be Transferred?

The simplest answer to this question is that a criticalist is best brought onto a case when a patient has a life-threatening condition and/or requires 24-hour care. Examples would include patients who require blood transfusions, patients in shock, polytrauma, cases of respiratory distress, diabetic ketoacidosis or hepatic lipidosis. These are complex cases that may require hour-to-hour or minute-to-minute changes in therapy, and these are the cases that DACVECCs dream of at night! Criticalists are also trained extensively in the treatment of life-threatening emergencies that may require immediate treatment such as placement of an emergency tracheostomy tube, pericardiocentesis or pleurocentesis.

DACVECCs are trained intensively in the pathophysiology of body systems and the complex interactions that may occur with multiple disease processes. Therefore, patients with numerous co-morbidities that require anesthesia for a surgical procedure may benefit from the surgery being performed in a hospital with a DACVECC. We may also serve as a first stop for a patient that needs urgent referral to another service. We work closely with the other specialists in the hospital if an urgent or same-day referral is required.

It is always important to weigh the risk of delayed treatment for these life-threatening conditions when considering a transfer. Drs. Kaplan and Sharpe welcome your calls at our Northfield hospital to talk through a case and consult on the options for your patient.

How Do Glucometers Work?

Most glucometers use test strips that are designed to draw up a defined volume of blood by capillary action. The blood reacts with enzymes embedded in the test strip that induce a color change or an electric charge. The glucometer translates the product of this enzyme reaction into a glucose measurement.

The AlphaTRAK glucometer requires much less blood (0.3 uL) than human glucometers.

Handheld glucometers are most frequently used to monitor treatment in diabetic patients. The AlphaTRAK® glucometer produced by Abbott Animal Health is presently our glucometer of choice. It has been calibrated for use in dogs and cats. Glucometers made for human use have been shown to be less accurate than the AlphaTRAK, especially at lower blood glucose concentrations.

This has been attributed to the higher plasma-to-red blood cell ratio of glucose molecules in dogs and cats compared to humans. A study comparing glucometers for use in 452 cats and dogs with and without diabetes mellitus found that glucose measurements from the AlphaTRAK glucometer fell within 2% of Antech Diagnostics laboratory measurements when run on the same blood sample. Other glucometers produced results which varied 21% to 39% from Antech glucose values.

The AlphaTRAK glucometer can also be used by pet owners to monitor their pet’s diabetes treatment at home. Home monitoring provides data more reflective of glucose values, which occur in pets while they participate in their regular daily routine. Easy-to-follow instructions for home use can be found at www.alphatrakmeter.com.

In cats, the marginal ear vein is the most common sample site. This is also an acceptable sample site in dogs.

For the dog only, the inner or outer lip offers an alternate sample site.

You Are What You Eat

Diet is an often overlooked component of treating dogs and cats with a variety of disorders. In our culture, pet owners are looking for the easy cure. And in our attempt to please our clients we get into the habit of prescribing the pill that will fix every illness. But is this really the best medicine? Maybe we should be taking a page from the human field where a significant number of illnesses are managed with recommendations for dietary changes, increased activity and stress reduction. Sure, it’s hard to get pet owners to change the way they are treating their pets. But it’s not enough to treat arthritis with just anti-inflammatory medications or a metabolic disease with anti-nausea medications. The appropriate dietary changes could reduce a pet’s need for medications.

Hill’s Pet Nutrition, a BluePearl Partner in Education, continues to research the roles diet plays in treating our pets’ diseases. They have recently introduced a number of new diets to treat patients afflicted with multiple conditions such as arthritis in overweight dogs and urinary tract issues in overweight cats as well as to reduce canine GI inflammation that may be related to stress or food sensitivities.

Give your Hill’s representative a call today to find out what diets you should be adding to your treatment arsenal.

Hill’s metabolic (feline urinary and canine mobility) diets

Hill’s digestive care diets have expanded to include sensitivity and stress recipes.

Eclampsia

Predisposition

Eclampsia, also known as postpartum hypocalcaemia or puerperal tetany, usually occurs between 21-28 days after delivery but can occur during parturition or late pregnancy. This condition typically occurs in small breed dogs or cats. Young age and large litter size in relation to body weight have also been reported to be predisposing factors.

Cause

Sudden decreases in ionized calcium concentrations cause increases in nerve cell membrane permeability to sodium ions. This causes an increased frequency in nerve transmission manifesting as muscle fasciculations. The severity of signs seen is a direct relation to the blood ionized calcium level, in addition to the rate in which the level decreases.

Clinical signs

Early signs include restlessness, salivation, whining, anorexia or vomiting. As the eclampsia becomes more severe, muscle fasciculations, tonic-clonic muscle spasms, tachycardia, hyperthermia and death may occur.

Diagnosis

Ionized calcium concentrations of 0.16 to 0.8 mmol/L are definitive for a diagnosis of eclampsia. If ionized calcium values are not available, signalment, history and clinical signs combined with total calcium levels in concentrations less than 1.625 mmol/L (<7 mg/dL) highly support a diagnosis.

Treatment

Calcium gluconate (10% solution) should be given slowly to effect (roughly 3-20 mls depending on the patient’s size). The muscle tremors will subside, and the patient will become more alert. An ECG should be monitored during administration and the rate decreased if arrhythmias or bradycardia is noted. An electrolyte panel and blood glucose level should be checked as electrolyte abnormalities and hypoglycemia may occur. Administer IV fluids to correct for dehydration. The pups/kittens should be removed from the dam/queen and hand fed. Calcium carbonate (50 mg/kg) PO every 8 hours should be given to help prevent relapse.

There may be a relapse with the next whelping/queening. Do not supplement with calcium during pregnancy as this may increase the chances of developing eclampsia.

ER Ingestions Crossword

Across 7. Natural insecticides common in some tick medications 9. Fruit that can be fatal to birds and rabbits 10. Vegetables that can cause vomiting and red cell damage 11. Theobromine and caffeine are the toxic element of this 12. Lily that varies in color and has leaves that sprout from the ground

Down 1. Fruit that is associated with renal failure (plural) 2. Common flower with white petals and yellow center 3. Can cause drunkenness, coma and death 4. Commonly called the Christmas flower 5. Common name for sago palm or cardboard palm 6. 5-carbon sugar alcohol, used in children’s multivitamins 8. Beer ingredient

FROM THE MEDICAL DIRECTOR

SNIFF…

Meet our new Medical Director Lauren Boyd, DVM, DACVIM

Lauren Boyd, DVM, DACVIM

Dr. Boyd received her doctor of veterinary medicine from The Ohio State University. She completed her internship at Veterinary Referral and Emergency Center in Norwalk CT and her residency at Animal Medical Center in New York City.

In her free time, Dr. Boyd enjoys reading, cooking, horseback riding and spending time with her husband and two children.

How do you like working with the primary care veterinary community?

Primary care veterinarians are the backbone of our specialty services, and I believe that without them, we cannot be successful. Our clients have an invaluable bond with their primary care veterinarians that has been built over the life of their four-legged family member, and often longer. Everyone benefits from the partnership that is created by the family veterinarian and the specialist. Clients trust their family veterinarian, whose confidence in our medicine and our process allows us to be able to help more pets and their families every day.

What keeps you interested in cases day after day?

As an internal medicine specialist, every case that walks in the door is different, and I never know what the day will bring. The combination of multiple disease processes in one pet fascinates and challenges me on a daily basis. I work with a tremendous group of people who are dedicated to excellent patient and client care, and it inspires me to be the best doctor and communicator that I can be.

What is the most interesting trip you have YET to take?

I have always wanted to go to the great young state of Alaska because the vastness of the untouched natural beauty is unparalleled. The wildlife in the national parks is tremendous, and the diverse landscape from mountains to glaciers is awe-inspiring.

Hospital Happenings

We would first like to thank everyone that attended our Cabin Fever 2016 day-long continuing education event; it was a huge success. For those who did not attend or could not make it, we hope to see you next year or at one of our monthly continuing education events held at our hospitals.

As the weather starts to get warmer and our surroundings are blossoming and growing, we are are pleased to announce some growth of our own. This summer we will launch BluePearl Portal, a platform allowing password-protected internet access to our medical records for both past and present patients that your clinical team has referred to our hospitals. Records will be accessible 24/7 through our website and, based on your preferences, you may elect to also receive faxes and/or email messages. The BluePearl Portal is designed to be easy to set up and easy to use. We will show you and your team how it works in person, and a helpful user guide will assist you further.

Of course, the BluePearl Portal is being provided in addition to the direct contact you receive from us for all of your cases.

We are dedicated to providing high-quality care and unsurpassed service, and we hope that you will allow us to continue to serve your clients in a way that is mutually beneficial.